This invention relates to a small-sized domestic refrigerator, and more particularly, to an electric ice making apparatus capable of automatically discharging ice pieces from a freezing tray incorporated therein.
Up to the present, there have been proposed a number of ice making apparatuses of the above described type each provided with an arrangement capable of automatically discharging ice pieces from a freezer or ice making tray incorporated therein. According to one typical arrangement, the ice pieces are automatically discharged from the freezer tray by means of a specific cam, which is conventionally mounted on the shaft of a driving motor. The driving motor per se is adapted to be stopped in response to a signal indicative of a deviation with respect to a predetermined temperature inside the freezing compartment of the refrigerator. More specifically, there is further provided a crank-pin capable of being driven by the rotation of the cam, so that the freezer tray and the cam are functionally associated. As soon as the cam is set free from the engagement with the crank-pin, after being driven through a predetermined angular distance, the freezer tray, which has been biased by a spring means, is adapted to be set free and to collide with a stop. By the collision between the stop and the freezer tray, the respective ice pieces in the freezer tray are separated from the tray and fall from the freezer tray. Alternatively, according to another typical arrangement, the freezer tray itself is rotated in one direction around a longitudinal axis by a rotational driving force, and full rotation is arranged to be prevented by a stop, so that the further application of the driving force to the stopped freezer tray causes the freezer tray to be twisted relative to the stop. After the respective ice pieces are separated from the tray and fall from the freezer tray by the action described above, the freezer tray is adapted to be turned in the opposite direction by a driving motor actuated by a change-over switch of the self-control type, thereby to cause the freezer tray to be disposed in the initial position. These conventional arrangements, however, have such deficiencies as described hereinbelow. As far as the former arrangement is concerned, the violent collision described above is indispensable, and damage to or destruction of parts of the device such as the driving motor etc. are inevitable. In addition, there is the production of a noise with each collision. On the other hand, according to the latter arrangement, the change-over switch of the self-control type is indispensable to cause the driving motor to be rotated in one or the other direction properly. Such provision of the change-over switch makes the electrical circuit means more complicated than for the former arrangement, with the result that the cost for manufacturing the refrigerator is undesirably increased.